A typical Loop set-up has a well-defined baseline that occurs most often and numerous variants which only differ from this baseline slightly. As a result, loopers have their personalities and memories from their baselines repeatedly reinforced by Loop memories from highly similar iterations. This allows them to better maintain a sense of 'self' even when hit with extremely divergent variations of their universe or the completely alien divergences common to fused Loops.

But not all Loops are like that. Some have multiple prominent variants that are able to serve as a baseline, to the point where Yggdrasil's damaged state isn't able to quite tell which is the 'true' baseline. This results in regular cycling through divergent histories, memories, and even personality variants until a looper's mind may not quite synch up with the current Loop iteration. In essence, they can no longer tell which of the various 'thems' crammed into their head is the 'real' them.

The syndrome was identified and quantified by Donatello of the TMNT Loops, after extensive study of himself, his three brothers, their adoptive father Splinter, and the most extreme case in their Loops: April O'Neil.

The worst sufferers, however, are known to hail from the Transformers Loops, with Wheeljack being the worst known case in the multiverse.

Symptoms of DLID include acting on Loop memories from a different iteration, erratic personality behavior, and, at the extreme ends of the condition, multiple personalities. The more divergent each of the regular 'selves' a looper experiences is, the more severe the symptoms can become.

Treatment can be difficult and long. Multiple Loops long. However, meditation and memory tricks for properly differentiating which Loop memories are most applicable to the current iteration work best. As does regular counseling if at all possible.

It is also entirely possible for somebody to embrace it, such as Lyra Heartstrings, in whose case there are four personalities that willingly work together.

April O'Neil: Possessing at least ten distinct and different histories that have gotten jumbled together, but thankfully no additional personalities.

Wheeljack: Unknown number of personalities, in conflict.

Lyra Heartstrings: Variant. Lyra's DLID came from her glitchy self-activation, which resulted in her getting several sets of Loop Memories whenever she Awakens. This has resulted in four (later increased to five and a half) separate personalities. Lyra has embraced this condition.

Shirou Emiya: Possesses three distinct Baseline histories, all of which he accepts as simultaneously valid. Due to his already alien mentality, each of his histories are of equal value in his mind and thus he has no additional personalities.